Various processes for producing aldehyde and/or alcohol compounds by the reaction of an ethylenically unsaturated compound with carbon monoxide and hydrogen in the presence of a catalyst are known. Typically, these reactions are performed at elevated temperatures and pressures. The aldehyde and alcohol compounds that are produced generally correspond to compounds obtained by the addition of a carbonyl or carbinol group, respectively, to an olefinically unsaturated carbon atom in the starting material with simultaneous saturation of the olefin bond. Isomerization of the olefin bond may take place to varying degrees under certain conditions; thus, as a consequence of this isomerization, a variety of products may be obtained. These processes are typically known as hydroformylation reactions and involve reactions which may be shown in the general case by the following equation:

In the above equation, each group R1 to R4 may independently represent an organic radical, for example a hydrocarbyl group, or a suitable atom such as a hydrogen or halogen atom, or a hydroxyl group. The above reaction may also be applied to a cycloaliphatic ring having an olefinic linkage, for example cyclohexene.
The catalyst employed in a hydroformylation reaction typically comprises a transition metal, such as cobalt, rhodium or ruthenium, in complex combination with carbon monoxide and ligand(s) such as an organophosphine.
Representative of the earlier hydroformylation methods which use transition metal catalysts having organophosphine ligands are described in U.S. Pat. Nos. 3,420,898, 3,501,515, 3,448,157, 3,440,291, 3,369,050 and 3,448,158.
In attempts to improve the efficiency of a hydroformylation process, attention has typically focussed on developing novel catalysts and novel processes for recovering and re-using the catalyst. In particular, novel catalysts have been developed which may exhibit improved stability at the required high reaction temperatures. Catalysts have also been developed which may permit the single-stage production of alcohols rather than a two-step procedure involving separate hydrogenation of the intermediate aldehyde. Moreover, homogeneous catalysts have been developed which may permit improved reaction rates whilst providing acceptable yields of the desired products.
Phosphabicyclohydrocarbyl ligands are known in the art, and their production and use in hydroformylation reactions are described in many prior art documents, including WO 2004/94440, WO 2003/82779, WO 2003/68719, WO 2003/68786, U.S. Pat. No. 7,012,162, WO 2000/52017, WO 2007/03589, WO 2004/56732 and WO 2004/54946.
Although the use of organophosphine ligands and organophosphine-modified metal catalysts provide very good results in the hydroformylation of ethylenically unsaturated compounds, the use of such ligands and catalysts is known to lead to the production of paraffins as a by-product. The paraffin by-products have very little commercial value. It would, therefore, be desirable to reduce the amount of paraffin by-products formed in a hydroformylation process. Further, it would be desirable to provide an improvement in the activity or reaction rate of a hydroformylation reaction over that catalysed by known metal catalyst systems.